This invention relates to a device for detecting the bacterial charge in a liquid or semi-liquid food product.
More specifically, the invention can be used in plant or machinery for the dairy industry and, more generally, in processing plant for the food industry.
The invention also relates to a machine for making and dispensing liquid and semi-liquid food products.
More specifically, but without limiting the scope of the invention, the machines referred to herein are machines for making and dispensing granitas, sorbets or slush drinks, ice creams, soft ice creams, whipped cream, yogurt and the like, as well as machines for making and storing mixes for ice cream, creams, sauces, soups, food mixes in general and the like.
As is known, machines of the above mentioned kind comprise a container for the basic product, consisting for example of whipping cream, ice cream product mixes, syrups and the like, and a feed circuit which is provided with devices such as refrigerating means for processing the basic product and at the end of which there are dispensing devices such as nozzles or taps adapted to deliver the finished product (whipped cream, ice cream, granita, etc.).
These machines, also considering the fact that the products they process are highly perishable, are subject to frequent checks and maintenance in order to guarantee optimum hygiene conditions along the entire feed circuit.
The main problem connected with the use of these machines for professional purposes is due to the presence of milk-based mixtures and the consequent need to clean and sanitize the machines in order to prevent the proliferation of germs and bacteria.
At present, a preventive maintenance procedure is carried out at specified intervals, from daily to twice-weekly, depending on machine characteristics. For example, machines without built-in heat treatment systems must be sanitized at least once every seventy-two hours, while self-pasteurizing machines are sanitized fortnightly.
In this regard, European patent application EP1716760, in the name of the same Applicant as this invention, discloses a machine for producing and dispensing liquid or semi-liquid consumer food products which is equipped with a washing device used to introduce, in alternate steps, into the feed and treatment circuit a flow of fluid in the liquid or vaporized state to allow the circuit to be washed and sanitized. A central processing unit controls and regulates the steps in the washing and sanitizing procedure.
Whether a machine must be disassembled for cleaning or is equipped with a built-in automatic sanitizing system, all the sanitizing operations are preventive and cannot guarantee conditions of total hygiene.
Although methods for estimating the cell mass of a bacterial population exist, these methods involve laboratory tests, high costs and extended times and are used, for example in the dairy industry, only in random testing.
To overcome these drawbacks, the Applicant has devised a machine for making and dispensing liquid or semi-liquid food products which is equipped with a device for checking the bacterial charge in both the basic and the finished product.
This device can determine the bacterial charge of the food product at any point on the machine.
The device, however, has some disadvantages connected with the precision of the measurements obtained. In effect, convective motions in the product inside the device upset and negatively affect measurement.